The founder, a Bavarian, was called Adi Dassler. So the correct pronunciation was always add ee dass (short e sound, not a long one). Although producing running shoes as early as the 1920s he only created the Adidas trademark in 1949.
Understandable that he preferred Adi to his given name of Adolf.
https://www.adidas-group.com/en/about/history/
Understandable that he preferred Adi to his given name of Adolf.
https://www.adidas-group.com/en/about/history/